The present invention relates to a foam material body for a pad, particularly a mattress.
Prior to a description of the present invention, it is believed to be advisable to define certain terms which will be utilized hereinafter. In the field to which the present invention pertains, the terms "lower mattress" and "upper mattress" are frequently used. In an element of furniture utilized for lying and provided with spring transverse battens (which are called in Switzerland "lattlicouch"), the lower mattress is formed by a batten grate. When the term "mattress" is mentioned in the following description and claims, it is utilized to identify the upper mattress.
It is known to provide foam material bodies for mattresses with throughgoing openings and passages which extend transverse to the direction of elongation of the mattress, so as to influence the deformability and to provide ventilation of the mattress. One such foam material body with several embodiments is disclosed, for example, in U.S. Pat. No. 3,885,257, which also discloses the respective pad. The foam material body is provided at both supporting surfaces with mutually intersecting channels, and the channels are arranged in pairs. In several embodiments the cutouts have a cross section with a thin initial portion which opens at one supporting surface of the body and an enlarged portion connected with the thin portion. The cross section of the enlarged portion is of for example substantially oval or rectangular shape. The dimension of the enlarged portions as measured in direction normal to the supporting surfaces is approximately equal to the dimension of the same measured parallel to the supporting surfaces. In these foam material bodies, mushroom-shaped pins are formed between the intersecting channels, each having a stem and a head. When the foam material body is loaded, for example, by a lying person, the head part extending laterally beyond the stem parts of the pins and not supported are considerably bent relative to the central longitudinal plane of the foam material body. The foam material body therefore has, in the event of provision of the above mentioned head parts, only a small carrying capacity, and the carrying capacity can be considerably different at different locations of the supporting surfaces, which is very undesirable. Since the stems of the pins can easily bend in all directions parallel to the supporting surfaces, the foam material body in the region of its supporting surfaces is also very soft, which is disadvantageous. The strong deformability of the pins, as well as the partially sharp-edged formation of the channels, is unfavorable for the service life of the foam material body. The webs which are formed along the longitudinal plane of symmetry in the center between the supporting surfaces and between two channels of each pair are limited in the known foam material body by concave faces or by mutually parallel flat faces. This formation of the webs contradicts a good deformability of the material body.